(I don't know about worker health problems, and I imagine that poor as Japan was at the time, any empiric data on it would be useless. But, anyway, I don't think the management structure is the correct place to fix that one problem.)
And I'll have to break into your Marxist narrative, but all that was once incredibly successful in a fully capitalist framework. It never became non-competitive, it was only replaced by order of top-down command structures.